Report No. : GEO Report No. 118

Report Title : Absolute Age-dating of Hong Kong Volcanic and Plutonic Rocks, Superficial Deposits, and Faults (2001), 153 p.

Author : R.J. Sewell & S.D.G. Campbell

Abstract

Over the past thirty years, with improvements in analytical techniques, absolute age-dating precisions have improved dramatically. As a result, absolute age-dating is now being used routinely to solve complex geological problems.

In Hong Kong, major advances in the understanding of geological relationships, particularly with regard to the volcanic and plutonic rocks have been achieved using age-dating. Radiometric dating has proved to be an effective tool for refining the existing geological maps and has complemented other analytical techniques including geochemistry, mineralogy and petrography, and seismic interpretation and borehole geophysics.

Recent developments in luminescence dating have enabled the dating of superficial deposits in Hong Kong. Refinements to the radiocarbon age-dating technique and the development of cosmogenic isotope techniques to date very young surfaces, also hold promise for dating colluvium. The use of these dating techniques, therefore, could have very significant applications in risk management strategy for natural terrain in Hong Kong.

Several outstanding structural problems still remain in Hong Kong, particularly with regard to the last age of movement on major faults and characterisation of the regional stress regime. These problems could be readily resolved by precise dating of the mafic and intermediate dykes, and the dating of fault-related materials.

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